/*

Copyright (c) 2009, Yahoo! Inc. All rights reserved.

Code licensed under the BSD License:

http://developer.yahoo.net/yui/license.txt

version: 3.0.0b1

build: 1163

*/

YUI.add('datasource-local', function(Y) {

/**

 * The DataSource utility provides a common configurable interface for widgets to

 * access a variety of data, from JavaScript arrays to online database servers.

 *

 * @module datasource

 */

/**

 * Provides the base DataSource implementation, which can be extended to

 * create DataSources for specific data protocols, such as the IO Utility, the

 * Get Utility, or custom functions.

 *

 * @module datasource

 * @submodule datasource-local

 */

/**

 * Base class for the DataSource Utility.

 * @class DataSource.Local

 * @extends Base

 * @constructor

 */    

var LANG = Y.Lang,

DSLocal = function() {

    DSLocal.superclass.constructor.apply(this, arguments);

};

    /////////////////////////////////////////////////////////////////////////////

    //

    // DataSource static properties

    //

    /////////////////////////////////////////////////////////////////////////////

Y.mix(DSLocal, {

    /**

     * Class name.

     *

     * @property NAME

     * @type String

     * @static     

     * @final

     * @value "dataSourceLocal"

     */

    NAME: "dataSourceLocal",

    /////////////////////////////////////////////////////////////////////////////

    //

    // DataSource Attributes

    //

    /////////////////////////////////////////////////////////////////////////////

    ATTRS: {

        /**

        * @attribute source

        * @description Pointer to live data.

        * @type MIXED

        * @default null        

        */

        source: {

            value: null

        }

    },

    /**

     * Global transaction counter.

     *

     * @property DataSource._tId

     * @type Number

     * @static

     * @private

     * @default 0

     */

    _tId: 0,

    /**

     * Executes a given callback.  The third param determines whether to execute

     *

     * @method DataSource.issueCallback

     * @param callback {Object} The callback object.

     * @param params {Array} params to be passed to the callback method

     * @param error {Boolean} whether an error occurred

     * @static

     */

    issueCallback: function (e) {

        if(e.callback) {

            var callbackFunc = (e.error && e.callback.failure) || e.callback.success;

            if (callbackFunc) {

                callbackFunc(e);

            }

        }

    }

});

Y.extend(DSLocal, Y.Base, {

    /**

    * Internal init() handler.

    *

    * @method initializer

    * @param config {Object} Config object.

    * @private        

    */

    initializer: function(config) {

        this._initEvents();

    },

    /**

    * This method creates all the events for this module.

    * @method _initEvents

    * @private        

    */

    _initEvents: function() {

        /**

         * Fired when a data request is received.

         *

         * @event request

         * @param e {Event.Facade} Event Facade with the following properties:

         * <dl>                          

         * <dt>tId (Number)</dt> <dd>Unique transaction ID.</dd>

         * <dt>request (Object)</dt> <dd>The request.</dd>

         * <dt>callback (Object)</dt> <dd>The callback object.</dd>

         * <dt>cfg (Object)</dt> <dd>Configuration object.</dd>

         * </dl>

         * @preventable _defRequestFn

         */

        this.publish("request", {defaultFn: Y.bind("_defRequestFn", this), queuable:true});

        /**

         * Fired when raw data is received.

         *

         * @event data

         * @param e {Event.Facade} Event Facade with the following properties:

         * <dl>

         * <dt>tId (Number)</dt> <dd>Unique transaction ID.</dd>

         * <dt>request (Object)</dt> <dd>The request.</dd>

         * <dt>callback (Object)</dt> <dd>The callback object with the following properties:

         *     <dl>

         *         <dt>success (Function)</dt> <dd>Success handler.</dd>

         *         <dt>failure (Function)</dt> <dd>Failure handler.</dd>

         *     </dl>

         * </dd>

         * <dt>cfg (Object)</dt> <dd>Configuration object.</dd>

         * <dt>data (Object)</dt> <dd>Raw data.</dd>

         * </dl>

         * @preventable _defDataFn

         */

        this.publish("data", {defaultFn: Y.bind("_defDataFn", this), queuable:true});

        /**

         * Fired when response is returned.

         *

         * @event response

         * @param e {Event.Facade} Event Facade with the following properties:

         * <dl>

         * <dt>tId (Number)</dt> <dd>Unique transaction ID.</dd>

         * <dt>request (Object)</dt> <dd>The request.</dd>

         * <dt>callback (Object)</dt> <dd>The callback object with the following properties:

         *     <dl>

         *         <dt>success (Function)</dt> <dd>Success handler.</dd>

         *         <dt>failure (Function)</dt> <dd>Failure handler.</dd>

         *     </dl>

         * </dd>

         * <dt>cfg (Object)</dt> <dd>Configuration object.</dd>

         * <dt>data (Object)</dt> <dd>Raw data.</dd>

         * <dt>response (Object)</dt> <dd>Normalized response object with the following properties:

         *     <dl>

         *         <dt>results (Object)</dt> <dd>Parsed results.</dd>

         *         <dt>meta (Object)</dt> <dd>Parsed meta data.</dd>

         *         <dt>error (Boolean)</dt> <dd>Error flag.</dd>

         *     </dl>

         * </dd>

         * </dl>

         * @preventable _defResponseFn

         */

         this.publish("response", {defaultFn: Y.bind("_defResponseFn", this), queuable:true});

        /**

         * Fired when an error is encountered.

         *

         * @event error

         * @param e {Event.Facade} Event Facade with the following properties:

         * <dl>

         * <dt>tId (Number)</dt> <dd>Unique transaction ID.</dd>

         * <dt>request (Object)</dt> <dd>The request.</dd>

         * <dt>callback (Object)</dt> <dd>The callback object with the following properties:

         *     <dl>

         *         <dt>success (Function)</dt> <dd>Success handler.</dd>

         *         <dt>failure (Function)</dt> <dd>Failure handler.</dd>

         *     </dl>

         * </dd>

         * <dt>cfg (Object)</dt> <dd>Configuration object.</dd>

         * <dt>data (Object)</dt> <dd>Raw data.</dd>

         * <dt>response (Object)</dt> <dd>Normalized response object with the following properties:

         *     <dl>

         *         <dt>results (Object)</dt> <dd>Parsed results.</dd>

         *         <dt>meta (Object)</dt> <dd>Parsed meta data.</dd>

         *         <dt>error (Object)</dt> <dd>Error object.</dd>

         *     </dl>

         * </dd>

         * </dl>

         */

    },

    /**

     * Manages request/response transaction. Must fire <code>response</code>

     * event when response is received. This method should be implemented by

     * subclasses to achieve more complex behavior such as accessing remote data.

     *

     * @method _defRequestFn

     * @param e {Event.Facade} Event Facadewith the following properties:

     * <dl>

     * <dt>tId (Number)</dt> <dd>Unique transaction ID.</dd>

     * <dt>request (Object)</dt> <dd>The request.</dd>

     * <dt>callback (Object)</dt> <dd>The callback object with the following properties:

     *     <dl>

     *         <dt>success (Function)</dt> <dd>Success handler.</dd>

     *         <dt>failure (Function)</dt> <dd>Failure handler.</dd>

     *     </dl>

     * </dd>

     * <dt>cfg (Object)</dt> <dd>Configuration object.</dd>

     * </dl>

     * @protected

     */

    _defRequestFn: function(e) {

        var data = this.get("source");

        // Problematic data

        if(LANG.isUndefined(data)) {

            e.error = new Error("Local source undefined");

        }

        if(e.error) {

            this.fire("error", e);

            Y.log("Error in response", "error", "datasource-local");

        }

        this.fire("data", Y.mix({data:data}, e));

        Y.log("Transaction " + e.tId + " complete. Request: " +

                Y.dump(e.request) + " . Response: " + Y.dump(e.response), "info", "datasource-local");

    },

    /**

     * Normalizes raw data into a response that includes results and meta properties.

     *

     * @method _defDataFn

     * @param e {Event.Facade} Event Facade with the following properties:

     * <dl>

     * <dt>tId (Number)</dt> <dd>Unique transaction ID.</dd>

     * <dt>request (Object)</dt> <dd>The request.</dd>

     * <dt>callback (Object)</dt> <dd>The callback object with the following properties:

     *     <dl>

     *         <dt>success (Function)</dt> <dd>Success handler.</dd>

     *         <dt>failure (Function)</dt> <dd>Failure handler.</dd>

     *     </dl>

     * </dd>

     * <dt>cfg (Object)</dt> <dd>Configuration object.</dd>

     * <dt>data (Object)</dt> <dd>Raw data.</dd>

     * </dl>

     * @protected

     */

    _defDataFn: function(e) {

        var data = e.data,

            meta = e.meta,

            response = {

                results: (LANG.isArray(data)) ? data : [data],

                meta: (meta) ? meta : {}

            };

        this.fire("response", Y.mix({response: response}, e));

    },

    /**

     * Sends data as a normalized response to callback.

     *

     * @method _defResponseFn

     * @param e {Event.Facade} Event Facade with the following properties:

     * <dl>

     * <dt>tId (Number)</dt> <dd>Unique transaction ID.</dd>

     * <dt>request (Object)</dt> <dd>The request.</dd>

     * <dt>callback (Object)</dt> <dd>The callback object with the following properties:

     *     <dl>

     *         <dt>success (Function)</dt> <dd>Success handler.</dd>

     *         <dt>failure (Function)</dt> <dd>Failure handler.</dd>

     *     </dl>

     * </dd>

     * <dt>cfg (Object)</dt> <dd>Configuration object.</dd>

     * <dt>data (Object)</dt> <dd>Raw data.</dd>

     * <dt>response (Object)</dt> <dd>Normalized response object with the following properties:

     *     <dl>

     *         <dt>results (Object)</dt> <dd>Parsed results.</dd>

     *         <dt>meta (Object)</dt> <dd>Parsed meta data.</dd>

     *         <dt>error (Boolean)</dt> <dd>Error flag.</dd>

     *     </dl>

     * </dd>

     * </dl>

     * @protected

     */

    _defResponseFn: function(e) {

        // Send the response back to the callback

        DSLocal.issueCallback(e);

    },

    /**

     * Generates a unique transaction ID and fires <code>request</code> event.

     *

     * @method sendRequest

     * @param request {Object} Request.

     * @param callback {Object} An object literal with the following properties:

     *     <dl>

     *     <dt><code>success</code></dt>

     *     <dd>The function to call when the data is ready.</dd>

     *     <dt><code>failure</code></dt>

     *     <dd>The function to call upon a response failure condition.</dd>

     *     <dt><code>argument</code></dt>

     *     <dd>Arbitrary data payload that will be passed back to the success and failure handlers.</dd>

     *     </dl>

     * @param cfg {Object} Configuration object

     * @return {Number} Transaction ID.

     */

    sendRequest: function(request, callback, cfg) {

        var tId = DSLocal._tId++;

        this.fire("request", {tId:tId, request:request, callback:callback, cfg:cfg || {}});

        Y.log("Transaction " + tId + " sent request: " + Y.dump(request), "info", "datasource-local");

        return tId;

    }

});

Y.namespace("DataSource").Local = DSLocal;

}, '3.0.0b1' ,{requires:['base']});